Graphene-based infrared position-sensitive detector for precise measurements and high-speed trajectory tracking.

Noncontact optical sensing plays an important role in various applications, for example, motion tracking, pilotless automobile, precision machining, and laser radars. A device with features of high resolution, fast response, and safe detection (operation wavelength at infrared (IR)) is highly desired in such applications. Here, a near IR position-sensitive detector constructed by graphene-Ge Schottky heterojunction has been demonstrated. The device shows high responsivity (minimum detectable power of similar to 10 nW), excellent spatial resolution (<1 mu m), fast response time (similar to mu s), and could operate in a wide spectral range (from visible to similar to 1600 nm). Applications of precise angle (similar to 5 x 10(-6) degree) and vibration frequency (up to 10 kHz) measurements, as well as the trajectory tracking of a high-speed infrared target (similar to 100 km/h), have been realized based on this device. This work therefore provides a promising route for a high-performance noncontact IR optical sensing system.